The presence of frost or ice on the most exposed and most critical structural elements of an aircraft, such as the wings, the tail and the stabilizers, can interfere with the operation of the aircraft. Basically, when there is an accumulation, the weight of the ice or snow added to the weight of the aircraft makes the aircraft heavier, so greater thrust is required for take-off. In addition, very slight surface roughness, as little as 0.4 mm thick, caused by the presence of ice or snow, changes the air flow affecting the aircraft's lift and rudders. The consequence of this roughness is substantially reduced lift, increased drag and less maneuverability of the aircraft, especially on the initial take-off and climb.
Another major consequence is due to the fact that the layers of ice that detach from the wings or the fuselage when the aircraft takes off or starts its climb can be sucked into the engines mounted on the rear of the fuselage, thus damaging or even stopping the engines. The layers of ice that detach can also cause damage due to their impact on critical surfaces such as the stabilizers.
There are currently means of detecting the presence of ice by making a tactile inspection or by using specially designed systems to detect ice, like ground ice detection systems (GIDS). But these means are difficult to use and are unsuited for an aircraft structure.
These means of detection are also separate from the means of defrosting. There are currently means of defrosting or removing ice during aerial operations under frosty conditions that consist of removing the frost or ice on the critical surfaces of the aircraft before take-off. To do so, physical-chemical means are used that consist of coating the critical surface with a product to limit and retard the formation of ice or putting an oozing liquid over the structure. These means require special facilities to supply them in airports. The defrosting liquid may cause clogging problems on the structure. These physical-chemical means also require the aircraft to be immobilized on the ground to defrost the critical surfaces. This takes a relatively long time before take-off and the presence of a qualified operator, thus entailing a relatively high cost.
There are also defrosting devices known for use when the aircraft is in flight, such as the device that uses a pneumatic system comprised of tubes of flexible material embedded in the leading edges whose alternating inflation and deflation break the ice when it has formed, or thermal defrosters composed of conduits for warm air taken from the engines. All these means require a major air supply, causing an increase in fuel consumption, thus hampering the performance of the turbojets. Such a device also requires enough space for the hoses and associated controls.
Thus far, there is no system that includes both means of detecting the presence of a layer of ice and means of defrosting to loosen the layer of ice in real time, particularly when the aircraft is in flight.